Use of Booster Sheds to Improve Performance of 800 kV Multicone Type Insulators Under Heavy Rain

Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV bushar insulators under heavy wetting conditions. Insulators were tested which are now used on si...     

Phase assembly and electrical conductivity of spark plasma sintered CeO2–ZrO2 ceramics

Ce _x Zr_1?x O₂ (x = 0.10, 0.16 and 0.33) nanocrystalline powders were obtained by a two-step synthesis technique and sintered by spark plasma sintering (SPS). As consequence of the reduction of Ce⁴⁺ to Ce³⁺ species by carbon in the graphite environment in SPS, phase assemblies including tetragonal, monoclinic and pyrochlore phases were generated in the ceramics during the sintering process. The electrical conductivity was highly dependent on phase assembly and atmosphere (N₂, H₂ and O₂). A significant decrease in the activation energy was noticed in the ceramics with high pyrochlore content when measuring the conductivity in H₂ atmosphere, consequence of the strong reduction promoted in these ceramics during the measurement. Equal conduction behavior with similar activation energy was observed in all the ceramics when measuring in O₂ atmosphere.     

The influence of depressive symptoms on experimental smoking and intention to smoke in a diverse youth sample.

Numerous studies have shown associations between smoking and depression, but the generalizability of the relationship across ethnic groups remains unknown. The present study assessed the association between depression and smoking intention and experimentation among adolescents from four ethnic groups in the Los Angeles area-Chinese/Chinese American, Latino/Hispanic, Persian/Iranian, and White. Over 800 7th graders in the Los Angeles area completed measures of depressive symptoms, experimentation with smoking, intention to smoke, and sociodemographic covariates. Chinese/Chinese American students had the lowest levels of depressive symptoms, whereas Latinos/Hispanics had the highest levels. Latinos/Hispanics also were the most likely to intend to smoke in the next year and were the most likely to have started experimenting with cigarette smoking. Depressive symptoms were significantly associated with intention to smoke even after controlling for language use acculturation, socioeconomic status, gender, and ethnicity. The association between depressive symptoms and intention to smoke did not vary significantly across ethnic groups. These results indicate that the association between depressive symptoms and adolescent smoking generalizes across diverse ethnic groups.     

Screening for molecules interacting with proteasomes in Thermoplasma acidophilum

Thermoplasma acidophilum cell extracts were fractionated by gel filtration. Proteasomes were eluted as two major peaks. The first one (molecular mass(r) about 2 MDa) contained proteasomes associated with DNA/protein complexes. Proteasomes eluted in the other peak were partially resolved into three subpeaks and based on their preferential hydrolysis of casein, Z-GGL-MCA, and suc-LLVY-MCA, were designated C, L and Y, respectively. Further purification of proteasomes from peak Y resulted in a homogenous enzyme preparation, whereas proteasomes purified from peak C contained a homomultimeric protein composed of 20 kDa subunits. Thus, association of proteasomes with this protein seems to be responsible for the observed increase in molecular mass and for inhibition of caseinolytic activity by Ca2+-ions.     

The effects of video feedback in the context of Milan Systemic therapy.

The authors compared the effectiveness of video feedback to verbal feedback within the context of Milan Systemic family therapy. Ten families were randomly assigned to either the video- or verbal-feedback condition, resulting in 16 participants in each condition. Families engaged in 5 wks of family therapy, which included either verbal or video feedback on a family interaction task. Changes from pretreatment to posttreatment were analyzed for several problem-related and family variables. Results indicated significant pretreatment posttreatment (controlling for family) interactions for responsibility for the problem and family adaptability. Support was found for the therapeutic effects of video feedback within Milan Systemic therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A 1-year prospective study of panic attacks: Clinical course and factors associated with maintenance.

A prospective naturalistic l-year follow-up study of 39 patients with current panic disorder, 17 remitted panic patients, 46 infrequent panickers, 22 patients with simple phobias, and 45 controls assessed clinical course and variables related to the maintenance of panic attacks. Nearly all panic disorder patients (92%) continued to experience panic attacks, and 41% of the initially remitted patients relapsed. No significant effects of treatments delivered in the community were found. Infrequent panickers tended to be more likely to develop panic disorder (15%) than controls (2%). Maintenance/relapse was most consistently linked with good heartbeat perception, anxiety sensitivity, and avoidance in the different subsamples. Patients with simple phobias or normal controls who experienced their first panic attack during follow-up had shown higher anxiety sensitivity at initial assessment than nonpanickers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DATA AUGMENTATION AND DYNAMIC LINEAR MODELS

Abstract. We define a subclass of dynamic linear models with unknown hyperpara-meter called d -inverse-gamma models. We then approximate the marginal probability density functions of the hyperparameter and the state vector by the data augmentation algorithm of Tanner and Wong. We prove that the regularity conditions for convergence hold. For practical implementation a forward-filtering-backward-sampling algorithm is suggested, and the relation to Gibbs sampling is discussed in detail.     

Oxidation Behavior of Rare-Earth Disilicate–Silicon Nitride Ceramics

The oxidation behavior and microstructure of the oxidized surfaces of RE₂Si₂O₇–Si₃N₄ ceramics were investigated. The high oxidation resistance of these materials at 1400°C is attributed to the minimization of amorphous phases via devitrification to disilicates that are in equilibrium with SiO₂, the oxidation product of Si₃N₄. Crystals of RE₂Si₂O₇ grew out of the surface silicate in prefered orientations that were dictated by crystal structure. The morphology of the microstructure of the oxidized surfaces was shown to be partially dependent on the concentration of impurities; the presence of Ca was found to coincide with the growth of Gd₂Si₂O₇ and Dy₂Si₂O₇ crystals with high aspect ratios.     

Overgeneral memory extends to pictorial retrieval cues and correlates with cognitive features in posttraumatic stress disorder.

Individuals with posttraumatic stress disorder (PTSD) show overgeneral memory (OGM) when retrieving autobiographical memories to word cues. We investigated whether OGM extends to picture cues and whether it is related to PTSD symptoms and cognitions. Trauma survivors with (n = 29) and without (n = 26) PTSD completed the standard Autobiographical Memory Test (AMT) and a novel picture version. Compared to the no-PTSD group, the PTSD group showed OGM in both test versions. Pictures facilitated specific memory retrieval, but this effect was no longer significant when verbal intelligence or depressive symptoms were controlled. OGM correlated with PTSD symptoms and perceived self-change; with intrusive memories, their perceived "nowness," responses to intrusions (thought suppression, rumination, dissociation), and negative interpretations of symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of protein kinase A and protein kinase C phosphorylation of the N-methyl-D-aspartate receptor NR1 subunit using phosphorylation site-specific antibodies

Modulation of N-methyl-D-aspartate receptors in the brain by protein phosphorylation may play a central role in the regulation of synaptic plasticity. To examine the phosphorylation of the NR1 subunit of N-methyl-D-aspartate receptors in situ, we have generated several polyclonal antibodies that recognize the NR1 subunit only when specific serine residues are phosphorylated. Using these antibodies, we demonstrate that protein kinase C (PKC) phosphorylates serine residues 890 and 896 and cAMP-dependent protein kinase (PKA) phosphorylates serine residue 897 of the NR1 subunit. Activation of PKC and PKA together lead to the simultaneous phosphorylation of neighboring serine residues 896 and 897. Phosphorylation of serine 890 by PKC results in the dispersion of surface-associated clusters of the NR1 subunit expressed in fibroblasts, while phosphorylation of serine 896 and 897 has no effect on the subcellular distribution of NR1. The PKC-induced redistribution of the NR1 subunit in cells occurs within minutes of serine 890 phosphorylation and reverses upon dephosphorylation. These results demonstrate that PKA and PKC phosphorylate distinct residues within a small region of the NR1 subunit and differentially affect the subcellular distribution of the NR1 subunit.